1. Field of the Invention
This invention relates to a composite sheet, to processes for making the composite sheet and to articles in which the composite sheet is incorporated. More particularly, the invention concerns such a composite sheet having a surface layer within which pile-like fibers are immobilized in a position that is generally vertical to the surface of the sheet. The composite sheet of the invention is highly resistant to abrasion.
2. Description of the Prior Art
It is known to combine various woven, knit or nonwoven fabrics with plastic sheets or resin layers to form composite sheets intended for use in thermoforming and molding processes. For example, Zafiroglu, U.S. Pat. No. 5,075,142, and Japanese Patent Application Publications 63-111050 and 63-162238 disclose such composite sheets. Miyagawa et al, U.S. Pat. No. 4,298,643, discloses a particular fabric having an exposed pile layer, the back of the fabric being bonded or laminated to a thermoplastic sheet. Although moldable composites have been utilized widely in many applications, such composites are in need of improvement when intended for use in articles that are subject to severe abrasion, such as athletic shoe parts, luggage corners and surface layers, protective work clothes, heavy-duty sacks and the like.
Pile fabrics, such as velvets, velours, terry cloths, moquettes, tufted fabrics, and the like, each have a surface layer in which fibers are generally vertical to the surface of the fabric. Certain stitchbonded fabrics in which a fibrous layer is contracted and buckled by means of elastic threads attached to the fibrous layer to form a layer of pile-like groups of fibers, are disclosed by Zafiroglu, U.S. Pat. Nos. 4,773,238 and 4,876,128. Generally, such pile or pile-like fabrics are not incorporated in composite sheets. However, Japanese Laid-open Patent Applications 64-85614 and 64-85615 disclose a floor mat which includes a tufted-monofilament pile, having an 8-mm height and a 0.08-g/cm.sup.3 pile fiber concentration, onto which a rubber resin is sprayed. The combination of the pile fiber and resin comprises 38 weight % resin and has an average density of 0.13 g/cm.sup.3. Increases in the abrasion resistance of such floor mats could significantly improve their utility.
An aim of the present invention is to provide a composite sheet that has high resistance to abrasion.